An on-board valve over-temperature protection circuit and method with self-detection function

Abstract

This invention relates to the field of control circuits, specifically to an airborne valve over-temperature protection circuit and method with self-testing function. The self-testing circuit is responsible for issuing a simulated self-test signal upon power-on and switching the signal source to a simulated self-test signal. During the power-on self-test, it performs simulated over-temperature verification on the temperature measuring circuit, monitoring circuit, latching circuit, and cut-off circuit. The temperature measuring circuit outputs the temperature sensor excitation signal and collects the temperature sensor feedback signal. The monitoring circuit issues an over-temperature alarm signal when the temperature exceeds a set threshold. The latching circuit stores the alarm signal from the monitoring circuit. The cut-off circuit is connected to the airborne valve power supply; when it receives a cut-off signal from the signal latching circuit, the power cut-off circuit cuts off the valve's power supply, closing the valve. This avoids the valve being accidentally powered on due to equipment restarts, program crashes, or other factors, improving circuit safety.

Description

Technical Field

[0001] This invention relates to the field of control circuits, specifically to an airborne valve over-temperature protection circuit and method with self-detection function. Background Technology

[0002] Civil airborne systems contain numerous valves, such as isolation valves and shut-off valves. Valve control is crucial, thus placing high demands on the safety of valve power shut-off circuits. Currently, most onboard valve shut-off circuits directly cut off power upon receiving a fault alarm signal. These circuits do not store the shut-off signal; power is restored to allow the valve to open again after a system restart or when the sensor alarm signal is cleared. For more severe fault modes, the airborne system shuts down after a fault occurs. Once the fault disappears, the system does not automatically return to normal; it must perform a self-check to ensure there are no problems before restoring power to the valve. Conventional valve shut-off circuits cannot meet these shut-off requirements. Summary of the Invention

[0003] Purpose of the invention The purpose of this invention is to provide an airborne valve over-temperature protection method and circuit with self-detection function. This invention combines hardware latching and software biting to ensure that after the airborne valve power supply is cut off due to over-temperature, it must receive a reset signal from the biting logic output in the CPU to restore the power supply. This avoids the situation where the valve is accidentally powered on due to other factors such as equipment restart or program crash, and improves the safety of the circuit.

[0004] Technical solution An airborne valve over-temperature protection circuit with self-detection function includes a self-test circuit, a temperature measuring circuit, a monitoring circuit, a latching circuit, and a shut-off circuit. The self-test circuit is connected to the temperature measuring circuit and is responsible for issuing a simulated self-test signal upon power-on and switching the signal source to a simulated self-test signal. During the power-on self-test, it performs simulated over-temperature verification on the temperature measuring circuit, monitoring circuit, latching circuit, and shut-off circuit. The temperature measuring circuit is responsible for outputting the temperature sensor excitation signal and collecting the temperature sensor feedback signal. The monitoring circuit is responsible for issuing an over-temperature alarm signal when the temperature exceeds a set threshold. The latching circuit stores the alarm signal from the monitoring circuit, and the over-temperature signal can only be cleared after receiving a reset signal. The shut-off circuit is connected to the airborne valve power supply. When it receives a shut-off signal from the signal latching circuit, the power shut-off circuit cuts off the power supply to the valve and closes the valve.

[0005] Furthermore, the self-test circuit includes a detection signal circuit and a switching circuit. The detection signal circuit includes a fourth reference source chip D4, a fifth operational amplifier chip D5, an eighteenth resistor R18, a nineteenth resistor R19, a twentieth resistor R20, a twenty-first resistor R20, a twenty-second resistor R22, a ninth capacitor C9, a tenth capacitor C10, an eleventh capacitor C11, a twelfth capacitor C12, and a thirteenth capacitor C13. Pin 2 of the fourth reference source chip D4 is connected to one end of the tenth capacitor C10 and the eleventh capacitor C11 and a +15V power supply. The other end of the tenth capacitor C10 and the eleventh capacitor C11 is connected to COM. Pin 6 of the fourth reference source chip D4 is connected to one end of the seventeenth resistor R17. The other end of resistor R17 is connected to capacitor C12 (12th capacitor) and pin 3 of op-amp chip D5 (5th operational amplifier chip). The other end of capacitor C12 is connected to COM. Pin 7 of op-amp chip D5 is connected to one end of capacitor C9 (9th capacitor) and the +15V power supply. The other end of capacitor C9 is connected to COM. Pin 4 of op-amp chip D5 is connected to one end of capacitor C13 (13th capacitor) and the -15V power supply. The other end of capacitor C13 is connected to COM. Pin 2 of op-amp chip D5 is connected to one end of resistors R19 (19th resistor) and R21 (21st resistor). The other end of resistor R21 is connected to COM. The other end of resistor R19 is connected to pin 6 of op-amp chip D5 and one end of resistor R18 (18th resistor). The other end of the eighteenth resistor R18 is connected to one end of the twentieth resistor R20 and the positive terminal of the detection signal. The other end of the twentieth resistor R20 is connected to the twenty-second resistor R22 and the negative terminal of the detection signal. The other end of the twenty-second resistor R22 is connected to COM. The above switching circuit includes the sixth analog switch chip D6, the thirty-first resistor R31, and the twenty-third capacitor C23. Pin 16 of the sixth analog switching chip D6 is connected to one end of the twenty-third capacitor C23. The other end of the twenty-third capacitor C23 is connected to COM. Pin 6 of the sixth analog switching chip D6 is connected to the thirty-first resistor R31 and COM. The other end of the thirty-first resistor R31 is connected to pin 15 of the sixth analog switching chip D6. Pin 2 of the sixth analog terminal chip D6 is connected to the positive terminal of the detection signal; pin 4 of the sixth analog terminal chip D6 is connected to the positive terminal of the temperature sensor signal; pin 9 of the sixth analog terminal chip D6 is connected to the negative terminal of the detection signal; pin 7 of the sixth analog terminal chip D6 is connected to the negative terminal of the temperature sensor signal; pin 1 of the sixth analog terminal chip D6 is connected to switch control signal 1; pin 10 of the sixth analog terminal chip D6 is connected to switch control signal 2; pin 11 of the sixth analog terminal chip D6 is connected to switch control signal 3; pin 20 of the sixth analog terminal chip D6 is connected to switch control signal 4; pin 3 of the sixth analog terminal chip D6 is connected to S2_HIGH; and pin 8 of the sixth analog terminal chip D6 is connected to S2_SENSE.

[0006] Furthermore, the fourth reference source chip D4 is specifically model REF5050AIDR, the fifth operational amplifier chip D5 is specifically model OPA197QDGKRQ1, and the sixth analog starter chip D6 is specifically model TMUX6234PWR.

[0007] Furthermore, the temperature measurement circuit includes a driving circuit and a signal acquisition circuit. The driving circuit includes a first reference source chip D1, a second operational amplifier chip D2, a third operational amplifier chip D3, a first resistor R1, a second resistor R3, a third resistor R3, a fourth resistor R4, a fifth resistor R5, a sixth resistor R6, a seventh resistor R7, an eighth resistor R8, a ninth resistor R9, a tenth resistor R10, an eleventh resistor R11, a twelfth resistor R12, a thirteenth resistor R13, a fourteenth resistor R14, a fifteenth resistor R15, a sixteenth resistor R16, a first capacitor C1, a second capacitor C2, a third capacitor C3, a fourth capacitor C4, a fifth capacitor C5, a sixth capacitor C6, a seventh capacitor C7, and an eighth capacitor C8. The first reference source chip D1 is also included. Pin 2 of source chip D1 is connected to one end of the first capacitor C1 and the second capacitor C2, and the +15V power supply. The other end of the first capacitor C1 and the second capacitor C2 is connected to COM. Pin 6 of the first reference source chip is connected to one end of the third capacitor C3 and the fourth capacitor C4, and the 5V reference source signal. The other end of the third capacitor C3 and the fourth capacitor C4 is connected to COM. Pin 2 of the second operational amplifier chip D2 is connected to one end of the first resistor R1 and the second resistor R2. The other end of the first resistor R1 is connected to COM. The other end of the second resistor R2 is connected to one end of the third resistor R3 and the fourth resistor R4, and pin 1 of the second operational amplifier chip D2. The other end of the third resistor R3 and the fourth resistor R4 is connected to one end of the seventh resistor R7, and the temperature sensor... The sensor's HIGH terminal signal is connected. The other end of the seventh resistor R7 is connected to pin 5 of the second operational amplifier D2. Pin 3 of the second operational amplifier D2 is connected to one end of the fifth resistor R5 and the sixth resistor R6. The other end of the fifth resistor R5 is connected to the 5V reference source signal. The other end of the sixth resistor R6 is connected to pins 7 and 6 of the second operational amplifier chip D2. Pin 11 of the second operational amplifier chip D2 is connected to one end of the fifth capacitor C5 and the -15V power supply. The other end of the fifth capacitor C5 is connected to COM. Pin 4 of the second operational amplifier chip D2 is connected to one end of the sixth capacitor C6 and the +15V power supply. The other end of the sixth capacitor C6 is connected to COM. Pin 9 of the second operational amplifier chip D2 is connected to the eighth resistor R8 and the ninth resistor R7. One end of resistor R9 is connected to the COM port. The other end of resistor R8 is connected to COM. The other end of resistor R9 is connected to one end of resistors R10 and R11, and to pin 8 of the second operational amplifier chip D2. The other ends of resistors R10 and R11 are connected to one end of resistor R14, and to the SENSE signal terminal of the temperature sensor. The other end of resistor R14 is connected to pin 12 of the second operational amplifier D2. Pin 10 of the second operational amplifier D2 is connected to one end of resistors R12 and R13. The other end of resistor R12 is connected to the 5V reference signal. The other end of resistor R13 is connected to pins 14 and 13 of the second operational amplifier chip D2.Pin 5 of the third op-amp chip D3 is connected to one end of the seventh capacitor C7, the eighth capacitor C8, the sixteenth resistor R16, and the LOW signal terminal of the temperature sensor. The other end of the seventh capacitor C7, the eighth capacitor C8, and the sixteenth resistor R16 is connected to COM. Pin 6 of the third op-amp chip D3 is connected to pin 7 of the third op-amp chip D3 and one end of the fifteenth resistor R15. The other end of the fifteenth resistor R15 is connected to the reference signal of the temperature sensor. The above signal acquisition circuit includes the seventh op-amp chip D7, the twenty-fifth resistor R25, the twenty-sixth resistor R26, and the thirtieth resistor R30. Pin 4 of the seventh op-amp chip D7 is connected to S2_HIGH, pin 1 of the seventh op-amp chip D7 is connected to S2_SENSE, pin 2 of the seventh op-amp chip D7 is connected to one end of the twenty-fifth resistor R25, the other end of the twenty-fifth resistor R25 is connected to pin 3 of the seventh op-amp chip D7, and pin 6 of the seventh op-amp chip D7 is connected to one point of the thirtieth resistor R30. The other end of the 30th resistor R30 is connected to COM. Pin 7 of the 7th operational amplifier chip D7 is connected to one end of the 26th resistor R26. The other end of the 26th resistor R26 is connected to the S_TEMP signal.

[0008] Furthermore, the first reference source chip D1 is specifically model REF5050AIDR, the second operational amplifier chip D2 is specifically model OPA4197QPWRQ1, the third operational amplifier chip D3 is specifically model OPA2197QDGKRQ1, and the seventh operational amplifier chip D7 is specifically model INA849DR.

[0009] Furthermore, the monitoring circuit includes a ninth comparator chip D9, a tenth reference source chip D10, a thirty-third resistor R33, a thirty-fourth resistor R34, a thirty-fifth resistor R35, a thirty-sixth resistor R36, a twenty-ninth capacitor C29, and a thirtieth capacitor C30. Pin 2 of the tenth reference source chip D10 is connected to the +15V power supply, one end of the twenty-ninth capacitor C29, and one end of the thirtieth capacitor C30. The other end of the twenty-ninth capacitor C29 and the thirtieth capacitor C30 is connected to COM. Pin 6 of the tenth reference source chip D10 is connected to one end of the thirty-sixth resistor R36. The other end of resistor R36 is connected to pin 2 of the ninth comparator chip. Pin 3 of the ninth comparator chip is connected to one end of resistor R35 and one end of resistor R33. The other end of resistor R35 is connected to the S_TEMP signal. The other end of resistor R33 is connected to pin 1 of the ninth comparator chip, one end of resistor R34, and the T2A95 signal. The other end of resistor R34 is connected to the 3.3V power supply. Pin 8 of the ninth comparator chip is connected to the 28V power supply. Pin 4 of the ninth comparator chip is connected to COM.

[0010] Furthermore, the ninth comparator chip D9 is specifically model REF5010AIDR, and the tenth reference source chip D10 is specifically model LM2903BQDRQ1.

[0011] Furthermore, the latching circuit includes an eleventh NOR gate chip D11, a twelfth NOR gate chip D12, a thirteenth OR gate chip D13, a thirty-seventh resistor R37, a thirty-eighth resistor R38, a thirty-ninth resistor R39, and a fortieth resistor R40. Pin 1 of the eleventh NOR gate chip D11 is connected to one end of the thirty-eighth resistor R38 and the RESET_TEMP2 reset signal; the other end of the thirty-eighth resistor R38 is connected to DGND. Pin 5 of the eleventh NOR gate chip D11 is connected to a 3.3V power supply. Pin 3 of the eleventh NOR gate chip D11 is connected to DGND. Pin 2 of the eleventh NOR gate chip D11 is connected to pin 4 of the twelfth NOR gate chip D12. Pin 4 of the eleventh NOR gate chip D11 is connected to pin 2 of the twelfth NOR gate chip D12 and the thirty-seventh resistor R37. One end of resistor 7 is connected to pin 1 of the thirteenth OR gate chip D13. The other end of the thirty-seventh resistor R37 is connected to DGND. Pin 1 of the twelfth NOR gate chip D12 is connected to one end of the fortieth resistor R40 and the T2A95 signal. The other end of the fortieth resistor R40 is connected to DGND. Pin 3 of the twelfth NOR gate chip D12 is connected to DGND. Pin 5 of the twelfth NOR gate chip D12 is connected to the 3.3V power supply. Pin 5 of the thirteenth OR gate chip D3 is connected to the 3.3V power supply. Pin 2 of the thirteenth OR gate chip D3 is connected to one end of the thirty-ninth resistor R39 and the T2A95 signal. The other end of the thirty-ninth resistor R39 is connected to DGND. Pin 3 of the thirteenth OR gate chip D3 is connected to DGND. Pin 4 of the thirteenth OR gate chip D3 is connected to the T2_AWARN signal.

[0012] Furthermore, the eleventh NOR gate chip D11 is specifically model SN74LVC1G02DBVR, the twelfth NOR gate chip D12 is specifically model SN74LVC1G02DBVR, and the thirteenth OR gate chip D13 is specifically model SN74LVC1G32QDCKRQ1.

[0013] Furthermore, the cutoff circuit includes a fifteenth inverter D15, a sixteenth switch chip D16, a first diode VD1, a forty-first resistor R41, a forty-second resistor R42, a forty-third resistor R43, a forty-fifth resistor R45, a forty-sixth resistor R46, a forty-sixth capacitor C46, ​​and a forty-seventh capacitor C47. Pin 5 of the fifteenth inverter D15 is connected to a 3.3V power supply; pin 3 of the fifteenth inverter D15 is connected to DGND; pin 2 of the fifteenth inverter D15 is connected to one end of the forty-first resistor R41 and the T2_AWARN signal; the other end of the forty-first resistor R41 is connected to DGND; pin 4 of the fifteenth inverter D15 is connected to one end of the forty-fifth resistor R45; the other end of the forty-fifth resistor R45 is connected to pin 1 of the sixteenth switch chip D16; and pin 8 of the sixteenth switch chip D16 is connected to... The 28V power supply is connected to one end of the 43rd resistor R43. The other end of the 43rd resistor R43 is connected to pin 2 of the 16th switch chip D16. Pin 4 of the 16th switch chip D16 is connected to one end of the 46th resistor R46. The other end of the 46th resistor R46 is connected to COM. Pin 7 of the 16th switch chip D16 is connected to one end of the first diode VD1. The other end of the first diode VD1 is connected to one end of the 42nd resistor R42 and the 28V_FB signal. The other end of the 42nd resistor R42 is connected to one end of the 46th capacitor C46 and the 28V_PWR signal. The other end of the 46th capacitor C46 is connected to COM. Pin 5 of the 16th switch chip D16 is connected to one end of the 47th capacitor C47. The other end of the 47th capacitor C47 is connected to pins 6 and 9 of the 16th switch chip D16 and COM.

[0014] Furthermore, the specific model of the fifteenth inverter D15 is SN74LVC1G14QDCKRQ1, and the specific model of the sixteenth switch chip D16 is TPS1H200AQDGNRQ1.

[0015] An airborne valve over-temperature protection method with self-detection function includes a self-detection circuit connected to a temperature measurement circuit. This circuit sends a simulated self-detection signal upon power-on and switches the signal source to the simulated self-detection signal to perform hardware circuit self-tests on the temperature measurement circuit, monitoring circuit, latching circuit, and cut-off circuit. The temperature measurement circuit includes a drive circuit and a signal acquisition circuit, responsible for outputting the temperature sensor excitation signal and acquiring the temperature sensor feedback signal. The monitoring circuit includes a comparison circuit and a reference source circuit, responsible for issuing an over-temperature alarm signal when the temperature exceeds a set threshold. The latching circuit stores the alarm signal from the monitoring circuit; the over-temperature signal is only cleared upon receiving a reset signal. The cut-off circuit is connected to the airborne valve power supply; upon receiving a cut-off signal from the signal latching circuit, the power cut-off circuit cuts off the 28V power supply to the valve, closing it. The method includes the following steps: Step 1: A method and circuit for over-temperature protection of airborne valves with self-testing function, characterized in that the self-testing circuit is used to test the accuracy of the over-temperature protection circuit of the airborne valve. During power-on self-test, the signal source is switched to the self-testing circuit, which generates a simulated self-testing signal and transmits it to the back-end temperature measurement circuit, isolation monitoring circuit, and cut-off circuit. The valve switch status signal is also sampled back to detect whether the 28V power supply to the airborne valve is cut off.

[0016] Step 2: A method and circuit for airborne valve over-temperature protection with self-testing function, characterized in that the system only operates normally after the self-testing circuit verifies that the airborne valve over-temperature protection circuit is functioning normally; if the power-on self-test of the self-testing circuit fails, the system reports a fault.

[0017] Step 3: An airborne valve over-temperature protection method and circuit with self-detection function, characterized in that the temperature measuring circuit includes a driving circuit and a signal acquisition circuit. The driving circuit is composed of a constant current source circuit, which is responsible for providing current excitation to the temperature sensor. The signal acquisition circuit is composed of a filtering circuit and a precision instrument amplification circuit, which is responsible for acquiring and processing the temperature sensor signal.

[0018] Step 4: An airborne valve over-temperature protection method and circuit with self-detection function, characterized in that the monitoring circuit includes a comparison circuit and a reference source circuit. The reference source circuit outputs a reference value A for the comparison circuit and a temperature alarm value B. The gain of the precision instrument amplification circuit in the temperature measurement circuit is G, where A=B*G. By configuring the value of G, alarms for different temperatures can be matched.

[0019] Step 5: An airborne valve over-temperature protection method and circuit with self-detection function, characterized in that the latching circuit is responsible for storing the over-temperature alarm signal issued by the monitoring circuit. The latching circuit will only clear the alarm signal after receiving a reset signal from the software BIT, ensuring that the cut-off signal issued by the latching circuit will not automatically recover due to the disappearance of the fault.

[0020] Step 6: A method and circuit for over-temperature protection of an airborne valve with self-detection function, characterized in that the power cut-off circuit controls the 28V power supply of the airborne valve. When the airborne system is running normally, 28V is connected and the airborne valve is open. When a fault signal occurs, the power cut-off circuit will cut off the 28V power supply of the airborne valve, and the valve will close, ensuring the safety of the airborne system.

[0021] Step 7: A method and circuit for over-temperature protection of an airborne valve with self-detection function, characterized in that the cut-off circuit controls the power supply of the airborne valve through a high-side switch. When a cut-off signal is received, the high-side switch cuts off the power supply to the valve, and the valve closes to ensure system safety.

[0022] Technical effect The purpose of this invention is to provide an airborne valve over-temperature protection method and circuit with self-detection function. After the self-test passes, the signal source is switched to a real signal. The temperature measurement circuit collects the temperature sensor signal, and the detection circuit determines whether the temperature exceeds the alarm value. When the temperature exceeds the alarm value, the detection circuit issues an over-temperature alarm signal. The over-temperature signal is transmitted to the signal latching circuit, which latches the over-temperature signal and generates a cut-off signal. The cut-off signal is transmitted to the cut-off circuit to cut off the valve power supply. This invention, through a combination of hardware latching and software bit-based methods, ensures that after the airborne valve power supply is cut off due to over-temperature, a reset signal from the bit logic output in the CPU must be received to restore power. This avoids the situation where the valve is accidentally powered on due to equipment restarts, program crashes, or other factors, thus improving circuit safety. Attached Figure Description

[0023] Figure 1 This is a self-test circuit diagram in one embodiment of the present invention; Figure 2 This is a temperature measurement circuit diagram in one embodiment of the present invention; Figure 3 This is a monitoring circuit diagram in one embodiment of the present invention; Figure 4 This is a latch circuit diagram in one embodiment of the present invention; Figure 5 This is a circuit diagram showing the cutting-off circuit in one embodiment of the present invention; Figure 6 This is a schematic diagram of an airborne valve power supply cut-off circuit according to the present invention; Detailed Implementation To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions in the embodiments of this invention will be described in more detail below. In the examples, the same or similar reference numerals denote the same or similar components or elements having the same or similar functions throughout. The described embodiments are some, but not all, of the embodiments of this invention. The embodiments described below with reference to reference are exemplary and intended to explain this invention, and should not be construed as limiting the invention. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention. The embodiments of this invention will be described in detail below.

[0024] The purpose of this invention is to provide an airborne valve over-temperature protection method and circuit with self-detection function, including a self-test circuit, a temperature measurement circuit, a monitoring circuit, a latching circuit, and a cut-off circuit. After the system is powered on, the self-test circuit first sends a simulated self-test signal, switching the signal source to a simulated self-test signal to perform a hardware circuit self-test and verify whether the hardware circuit itself is normal. After the self-test passes, the signal source is switched to a real signal, the temperature measurement circuit collects the temperature sensor signal, and the detection circuit determines whether the temperature exceeds the alarm value. When the temperature exceeds the alarm value, the detection circuit sends an over-temperature alarm signal, which is transmitted to the signal latching circuit. The signal latching circuit latches the over-temperature signal and generates a cut-off signal, which is transmitted to the cut-off circuit to cut off the power supply to the valve. The temperature measurement circuit of this invention consists of a drive circuit and a signal acquisition circuit, enabling high-precision acquisition of temperature sensor signals. This invention also incorporates a self-test circuit that performs simulated over-temperature verification on the temperature measurement circuit, monitoring circuit, latching circuit, and cut-off circuit during power-on self-testing, ensuring normal circuit function. Furthermore, this invention combines hardware latching with software bit-based technology to ensure that if the onboard valve power supply is cut off due to over-temperature, a reset signal from the CPU's bit logic output is required to restore power. This avoids situations where the valve is mistakenly powered on due to equipment restarts, program crashes, or other factors, thus improving circuit safety.

[0025] Example An airborne valve over-temperature protection circuit with self-detection function includes a self-detection circuit, a temperature measuring circuit, a monitoring circuit, a latching circuit, and a cut-off circuit; Preferably, further, the self-test circuit includes a detection signal circuit and a switching circuit, wherein, in combination with Figure 1The aforementioned detection signal circuit includes a fourth reference source chip D4, a fifth operational amplifier chip D5, an eighteenth resistor R18, a nineteenth resistor R19, a twentieth resistor R20, a twenty-first resistor R20, a twenty-second resistor R22, a ninth capacitor C9, a tenth capacitor C10, an eleventh capacitor C11, a twelfth capacitor C12, and a thirteenth capacitor C13. Pin 2 of the fourth reference source chip D4 is connected to one end of the tenth capacitor C10 and the eleventh capacitor C11, and a +15V power supply. The other end of the tenth capacitor C10 and the eleventh capacitor C11 is connected to COM. Pin 6 of the fourth reference source chip D4 is connected to one end of the seventeenth resistor R17, and the other end of the seventeenth resistor R17 is connected to the twelfth capacitor C9. 12. Pin 3 of the fifth op-amp chip D5 is connected to the COM port. The other end of the twelfth capacitor C12 is connected to COM. Pin 7 of the fifth op-amp chip is connected to one end of the ninth capacitor C9 and the +15V power supply. The other end of the ninth capacitor C9 is connected to COM. Pin 4 of the fifth op-amp chip is connected to one end of the thirteenth capacitor C13 and the -15V power supply. The other end of the thirteenth capacitor C13 is connected to COM. Pin 2 of the fifth op-amp chip D5 is connected to one end of the nineteenth resistor R19 and the twenty-first resistor R21. The other end of the twenty-first resistor R21 is connected to COM. The other end of the nineteenth resistor R19 is connected to pin 6 of the fifth op-amp chip and one end of the eighteenth resistor R18. The other end of the eighteenth resistor R18... One end of the 20th resistor R20 is connected to the positive terminal of the detection signal; the other end of the 20th resistor R20 is connected to the 22nd resistor R22 and the negative terminal of the detection signal; the other end of the 22nd resistor R22 is connected to COM. The aforementioned switching circuit includes a sixth analog switch chip D6, a 31st resistor R31, and a 23rd capacitor C23. Pin 16 of the sixth analog switch chip D6 is connected to one end of the 23rd capacitor C23; the other end of the 23rd capacitor C23 is connected to COM. Pin 6 of the sixth analog switch chip D6 is connected to the 31st resistor R31 and COM; the other end of the 31st resistor R31 is connected to pin 15 of the sixth analog switch chip D6. Pin 2 is connected to the positive terminal of the detection signal. Pin 4 of the sixth analog start chip D6 is connected to the positive terminal of the temperature sensor signal. Pin 9 of the sixth analog start chip D6 is connected to the negative terminal of the detection signal. Pin 7 of the sixth analog start chip D6 is connected to the negative terminal of the temperature sensor signal. Pin 1 of the sixth analog start chip D6 is connected to switch control signal 1. Pin 10 of the sixth analog start chip D6 is connected to switch control signal 2. Pin 11 of the sixth analog start chip D6 is connected to switch control signal 3. Pin 20 of the sixth analog start chip D6 is connected to switch control signal 4. Pin 3 of the sixth analog start chip D6 is connected to S2_HIGH. Pin 8 of the sixth analog start chip D6 is connected to S2_SENSE.

[0026] Furthermore, the fourth reference source chip D4 is specifically model REF5050AIDR, the fifth operational amplifier chip D5 is specifically model OPA197QDGKRQ1, and the sixth analog starter chip D6 is specifically model TMUX6234PWR.

[0027] Preferably, further, the temperature measuring circuit includes a driving circuit and a signal acquisition circuit, wherein, combined with Figure 2The aforementioned driving circuit includes a first reference source chip D1, a second operational amplifier chip D2, a third operational amplifier chip D3, a first resistor R1, a second resistor R3, a third resistor R3, a fourth resistor R4, a fifth resistor R5, a sixth resistor R6, a seventh resistor R7, an eighth resistor R8, a ninth resistor R9, a tenth resistor R10, an eleventh resistor R11, a twelfth resistor R12, a thirteenth resistor R13, a fourteenth resistor R14, a fifteenth resistor R15, a sixteenth resistor R16, a first capacitor C1, a second capacitor C2, a third capacitor C3, a fourth capacitor C4, a fifth capacitor C5, a sixth capacitor C6, a seventh capacitor C7, and an eighth capacitor C8. Pin 2 of the first reference source chip D1 is connected to one end of the first capacitor C1 and the second capacitor C2, and +1. A 5V power supply is connected. The other ends of the first capacitor C1 and the second capacitor C2 are connected to COM. Pin 6 of the first reference source chip is connected to one end of the third capacitor C3 and the fourth capacitor C4, and the 5V reference source signal. The other ends of the third capacitor C3 and the fourth capacitor C4 are connected to COM. Pin 2 of the second operational amplifier chip D2 is connected to one end of the first resistor R1 and the second resistor R2. The other end of the first resistor R1 is connected to COM. The other end of the second resistor R2 is connected to one end of the third resistor R3 and the fourth resistor R4, and pin 1 of the second operational amplifier chip D2. The other ends of the third resistor R3 and the fourth resistor R4 are connected to one end of the seventh resistor R7, and the HIGH signal of the temperature sensor. The other end of the seventh resistor R7 is connected to pin 5 of the second operational amplifier D2. Pin 3 of operational amplifier D2 is connected to one end of resistors R5 and R6. The other end of resistor R5 is connected to a 5V reference signal. The other end of resistor R6 is connected to pins 7 and 6 of operational amplifier D2. Pin 11 of operational amplifier D2 is connected to one end of capacitor C5 and a -15V power supply. The other end of capacitor C5 is connected to COM. Pin 4 of operational amplifier D2 is connected to one end of capacitor C6 and a +15V power supply. The other end of capacitor C6 is connected to COM. Pin 9 of operational amplifier D2 is connected to one end of resistors R8 and R9. The other end of resistor R8 is connected to COM. The other end of resistor R9 is connected to resistor R10. One end of the eleventh resistor R11 is connected to pin 8 of the second operational amplifier chip D2. The other ends of the first and eleventh resistors R10 and R11 are connected to one end of the fourteenth resistor R14 and the SENSE signal terminal of the temperature sensor. The other end of the fourteenth resistor R14 is connected to pin 12 of the second operational amplifier D2. Pin 10 of the second operational amplifier D2 is connected to one end of the twelfth resistor R12 and the thirteenth resistor R13. The other end of the twelfth resistor R12 is connected to the 5V reference signal. The other end of the thirteenth resistor R13 is connected to pins 14 and 13 of the second operational amplifier chip D2. Pin 5 of the third operational amplifier chip D3 is connected to one end of the seventh capacitor C7, the eighth capacitor C8, and the sixteenth resistor R16 and the LOW signal terminal of the temperature sensor.The seventh capacitor C7, the eighth capacitor C8, and the other end of the sixteenth resistor R16 are connected to COM. Pin 6 of the third operational amplifier chip D3 is connected to pin 7 of the third operational amplifier chip D3, and one end of the fifteenth resistor R15. The other end of the fifteenth resistor R15 is connected to the temperature sensor reference signal. The above signal acquisition circuit includes the seventh operational amplifier chip D7, the twenty-fifth resistor R25, the twenty-sixth resistor R26, and the thirtieth resistor R30. Pin 4 of the seventh operational amplifier chip D7 is connected to S2_HIGH, pin 1 of the seventh operational amplifier chip D7 is connected to S2_SENSE, pin 2 of the seventh operational amplifier chip D7 is connected to one end of the twenty-fifth resistor R25, the other end of the twenty-fifth resistor R25 is connected to pin 3 of the seventh operational amplifier chip D7, and pin 6 of the seventh operational amplifier chip D7 is connected to one point of the thirtieth resistor R30. The other end of the thirtieth resistor R30 is connected to COM. Pin 7 of the seventh operational amplifier chip D7 is connected to one end of the twenty-sixth resistor R26, and the other end of the twenty-sixth resistor R26 is connected to the S_TEMP signal. ,

[0028] Furthermore, the first reference source chip D1 is specifically model REF5050AIDR, the second operational amplifier chip D2 is specifically model OPA4197QPWRQ1, the third operational amplifier chip D3 is specifically model OPA2197QDGKRQ1, and the seventh operational amplifier chip D7 is specifically model INA849DR.

[0029] Preferably, further, the monitoring circuit includes a ninth comparator chip D9, a tenth reference source chip D10, a thirty-third resistor R33, a thirty-fourth resistor R34, a thirty-fifth resistor R35, a thirty-sixth resistor R36, a twenty-ninth capacitor C29, and a thirtieth capacitor C30. Pin 2 of the tenth reference source chip D10 is connected to a +15V power supply, one end of the twenty-ninth capacitor C29, and one end of the thirtieth capacitor C30. The other end of the twenty-ninth capacitor C29 and the thirtieth capacitor C30 is connected to COM. Pin 6 of the tenth reference source chip D10 is connected to one end of the thirty-sixth resistor R36. The other end of the thirty-sixth resistor R36 is connected to pin 2 of the ninth comparator chip. Pin 3 of the ninth comparator chip is connected to one end of the thirty-fifth resistor R35 and one end of the thirty-third resistor R33. The other end of the thirty-fifth resistor R35 is connected to the S_TEMP signal. The other end of the thirty-third resistor R33 is connected to pin 1 of the ninth comparator chip, one end of the thirty-fourth resistor R34, and the T2A95 signal. The other end of the thirty-fourth resistor R34 is connected to the 3.3V power supply. Pin 8 of the ninth comparator chip is connected to the 28V power supply. Pin 4 of the ninth comparator chip is connected to COM.

[0030] Furthermore, the ninth comparator chip D9 is specifically model REF5010AIDR, and the tenth reference source chip D10 is specifically model LM2903BQDRQ1.

[0031] Preferably, further, the latching circuit includes an eleventh NOR gate chip D11, a twelfth NOR gate chip D12, a thirteenth OR gate chip D13, a thirty-seventh resistor R37, a thirty-eighth resistor R38, a thirty-ninth resistor R39, and a fortieth resistor R40; pin 1 of the eleventh NOR gate chip D11 is connected to one end of the thirty-eighth resistor R38 and the RESET_TEMP2 reset signal, and the other end of the thirty-eighth resistor R38 is connected to DGND; pin 5 of the eleventh NOR gate chip D11 is connected to a 3.3V power supply; pin 3 of the eleventh NOR gate chip D11 is connected to DGND; pin 2 of the eleventh NOR gate chip D11 is connected to pin 4 of the twelfth NOR gate chip D12; and pin 4 of the eleventh NOR gate chip D11 is connected to pin 2 of the twelfth NOR gate chip D12 and the fortieth resistor R40. One end of resistor R37 is connected to pin 1 of the thirteenth OR gate chip D13. The other end of resistor R37 is connected to DGND. Pin 1 of the twelfth NOR gate chip D12 is connected to one end of resistor R40 and the T2A95 signal. The other end of resistor R40 is connected to DGND. Pin 3 of the twelfth NOR gate chip D12 is connected to DGND. Pin 5 of the twelfth NOR gate chip D12 is connected to the 3.3V power supply. Pin 5 of the thirteenth OR gate chip D3 is connected to the 3.3V power supply. Pin 2 of the thirteenth OR gate chip D3 is connected to one end of resistor R39 and the T2A95 signal. The other end of resistor R39 is connected to DGND. Pin 3 of the thirteenth OR gate chip D3 is connected to DGND. Pin 4 of the thirteenth OR gate chip D3 is connected to the T2_AWARN signal.

[0032] Furthermore, the eleventh NOR gate chip D11 is specifically model SN74LVC1G02DBVR, the twelfth NOR gate chip D12 is specifically model SN74LVC1G02DBVR, and the thirteenth OR gate chip D13 is specifically model SN74LVC1G32QDCKRQ1.

[0033] Preferably, further, the cutoff circuit includes a fifteenth inverter D15, a sixteenth switch chip D16, a first diode VD1, a forty-first resistor R41, a forty-second resistor R42, a forty-third resistor R43, a forty-fifth resistor R45, a forty-sixth resistor R46, a forty-sixth capacitor C46, ​​and a forty-seventh capacitor C47; pin 5 of the fifteenth inverter D15 is connected to a 3.3V power supply, pin 3 of the fifteenth inverter D15 is connected to DGND, pin 2 of the fifteenth inverter D15 is connected to one end of the forty-first resistor R41 and the T2_AWARN signal, the other end of the forty-first resistor R41 is connected to DGND, pin 4 of the fifteenth inverter D15 is connected to one end of the forty-fifth resistor R45, the other end of the forty-fifth resistor R45 is connected to pin 1 of the sixteenth switch chip D16, and pin 8 of the sixteenth switch chip D16... Pin 1 is connected to the 28V power supply and one end of the 43rd resistor R43. The other end of the 43rd resistor R43 is connected to pin 2 of the 16th switch chip D16. Pin 4 of the 16th switch chip D16 is connected to one end of the 46th resistor R46. The other end of the 46th resistor R46 is connected to COM. Pin 7 of the 16th switch chip D16 is connected to one end of the first diode VD1. The other end of the first diode VD1 is connected to one end of the 42nd resistor R42 and the 28V_FB signal. The other end of the 42nd resistor R42 is connected to one end of the 46th capacitor C46 and the 28V_PWR signal. The other end of the 46th capacitor C46 is connected to COM. Pin 5 of the 16th switch chip D16 is connected to one end of the 47th capacitor C47. The other end of the 47th capacitor C47 is connected to pins 6 and 9 of the 16th switch chip D16 and COM.

[0034] Furthermore, the specific model of the fifteenth inverter D15 is SN74LVC1G14QDCKRQ1, and the specific model of the sixteenth switch chip D16 is TPS1H200AQDGNRQ1.

[0035] 2. Method: A method for over-temperature protection of airborne valves with self-detection function, combined with Figure 6The self-test circuit is connected to the temperature measurement circuit and is responsible for issuing a simulated self-test signal upon power-on, switching the signal source to a simulated self-test signal, and performing a hardware circuit self-test. This includes power-on self-tests of the temperature measurement circuit, monitoring circuit, latching circuit, and cut-off circuit. The temperature measurement circuit includes a drive circuit and a signal acquisition circuit, responsible for outputting the temperature sensor excitation signal and acquiring the temperature sensor feedback signal. The monitoring circuit includes a comparison circuit and a reference source circuit, responsible for issuing an over-temperature alarm signal when the temperature exceeds a set threshold. The latching circuit stores the alarm signal from the monitoring circuit; the over-temperature signal can only be cleared upon receiving a reset signal. The cut-off circuit is connected to the airborne valve power supply. When it receives a cut-off signal from the signal latching circuit, the power cut-off circuit cuts off the 28V power supply to the valve, closing it. The steps include: Step 1: A method and circuit for over-temperature protection of airborne valves with self-testing function, characterized in that the self-testing circuit is used to test the accuracy of the over-temperature protection circuit of the airborne valve. During power-on self-test, the signal source is switched to the self-testing circuit, which generates a simulated self-testing signal and transmits it to the back-end temperature measurement circuit, isolation monitoring circuit, and cut-off circuit. The valve switch status signal is also sampled back to detect whether the 28V power supply to the airborne valve is cut off.

[0036] Step 2: A method and circuit for airborne valve over-temperature protection with self-testing function, characterized in that the system only operates normally after the self-testing circuit verifies that the airborne valve over-temperature protection circuit is functioning normally; if the power-on self-test of the self-testing circuit fails, the system reports a fault.

[0037] Step 3: An airborne valve over-temperature protection method and circuit with self-detection function, characterized in that the temperature measuring circuit includes a driving circuit and a signal acquisition circuit. The driving circuit is composed of a constant current source circuit, which is responsible for providing current excitation to the temperature sensor. The signal acquisition circuit is composed of a filtering circuit and a precision instrument amplification circuit, which is responsible for acquiring and processing the temperature sensor signal.

[0038] Step 4: An airborne valve over-temperature protection method and circuit with self-detection function, characterized in that the monitoring circuit includes a comparison circuit and a reference source circuit. The reference source circuit outputs a reference value A for the comparison circuit and a temperature alarm value B. The gain of the precision instrument amplification circuit in the temperature measurement circuit is G, where A=B*G. By configuring the value of G, alarms for different temperatures can be matched.

[0039] Step 5: An airborne valve over-temperature protection method and circuit with self-detection function, characterized in that the latching circuit is responsible for storing the over-temperature alarm signal issued by the monitoring circuit. The latching circuit will only clear the alarm signal after receiving a reset signal from the software BIT, ensuring that the cut-off signal issued by the latching circuit will not automatically recover due to the disappearance of the fault.

[0040] Step 6: A method and circuit for over-temperature protection of an airborne valve with self-detection function, characterized in that the power cut-off circuit controls the 28V power supply of the airborne valve. When the airborne system is running normally, 28V is connected and the airborne valve is open. When a fault signal occurs, the power cut-off circuit will cut off the 28V power supply of the airborne valve, and the valve will close, ensuring the safety of the airborne system.

[0041] Step 7: A method and circuit for over-temperature protection of an airborne valve with self-detection function, characterized in that the cut-off circuit controls the power supply of the airborne valve through a high-side switch. When a cut-off signal is received, the high-side switch cuts off the power supply to the valve, and the valve closes to ensure system safety.

[0042] Furthermore, unless otherwise defined, the technical or scientific terms used in this application description shall have the ordinary meaning understood by one of ordinary skill in the art. The terms "upper," "lower," "left," "right," "center," "vertical," "horizontal," "inner," and "outer," etc., used in this application description to indicate relative direction or positional relationship are used only to indicate relative orientation or positional relationship, and do not imply that the device or component must have a specific orientation, or be constructed and operated in a specific orientation. When the absolute position of the described object changes, its relative positional relationship may also change accordingly, and therefore should not be construed as a limitation on this application. The terms "first," "second," "third," and similar terms used in this application description are used for descriptive purposes only to distinguish different components, and should not be construed as indicating or implying relative importance. The terms "a," "one," or "the," etc., used in this application description should not be construed as an absolute limitation on quantity, but should be construed as indicating the existence of at least one. The terms "including," "comprising," etc., used in this application description mean that the element or object preceding the word covers the element or object listed after the word and its equivalents, without excluding other elements or objects.

[0043] Furthermore, it should be noted that, unless otherwise explicitly specified and limited, terms such as “installation,” “connection,” and “linkage” used in the description of this application should be interpreted broadly. For example, a connection can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium; or it can be a connection within two components. Those skilled in the art can understand its specific meaning in this application according to the specific circumstances.

[0044] The above description is merely a specific embodiment of the present invention and is not intended to limit the present invention. Within the spirit and principles of the present invention, any person skilled in the art may use the above-disclosed technical content to make changes or modifications to equivalent embodiments and apply them to other fields. However, any simple modifications, equivalent changes and modifications made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solution of the present invention, as well as any modifications, equivalent substitutions, improvements, etc., should be included within the protection scope of the present invention.

Claims

1. An airborne valve over-temperature protection circuit with self-detection function, characterized in that, It includes a self-test circuit, a temperature measurement circuit, a monitoring circuit, a latching circuit, and a cut-off circuit. The self-test circuit is connected to the temperature measurement circuit and is responsible for sending a simulated self-test signal upon power-on and switching the signal source to a simulated self-test signal. During the power-on self-test, it performs simulated over-temperature verification on the temperature measurement circuit, monitoring circuit, latching circuit, and cut-off circuit. The temperature measurement circuit is responsible for outputting the temperature sensor excitation signal and collecting the temperature sensor feedback signal. The monitoring circuit is responsible for issuing an over-temperature alarm signal when the temperature exceeds the set threshold. The latching circuit stores the alarm signal from the monitoring circuit, and the over-temperature signal can only be cleared after receiving a reset signal. The cut-off circuit is connected to the airborne valve power supply. When it receives a cut-off signal from the signal latching circuit, the power cut-off circuit will cut off the power supply to the valve and close the valve.

2. The circuit as described in claim 1, characterized in that, The self-test circuit includes a detection signal circuit and a switching circuit. The detection signal circuit includes a fourth reference source chip D4, a fifth operational amplifier chip D5, an eighteenth resistor R18, a nineteenth resistor R19, a twentieth resistor R20, a twenty-first resistor R20, a twenty-second resistor R22, a ninth capacitor C9, a tenth capacitor C10, an eleventh capacitor C11, a twelfth capacitor C12, and a thirteenth capacitor C13. Pin 2 of the fourth reference source chip D4 is connected to one end of the tenth capacitor C10 and the eleventh capacitor C11 and a +15V power supply. The other end of the tenth capacitor C10 and the eleventh capacitor C11 is connected to COM. Pin 6 of the fourth reference source chip D4 is connected to one end of the seventeenth resistor R17. The other end of R17 is connected to the twelfth capacitor C12 and pin 3 of the fifth op-amp chip D5. The other end of the twelfth capacitor C12 is connected to COM. Pin 7 of the fifth op-amp chip is connected to one end of the ninth capacitor C9 and the +15V power supply. The other end of the ninth capacitor C9 is connected to COM. Pin 4 of the fifth op-amp chip is connected to one end of the thirteenth capacitor C13 and the -15V power supply. The other end of the thirteenth capacitor C13 is connected to COM. Pin 2 of the fifth op-amp chip D5 is connected to one end of the nineteenth resistor R19 and the twenty-first resistor R21. The other end of the twenty-first resistor R21 is connected to COM. The other end of the nineteenth resistor R19 is connected to pin 6 of the fifth op-amp chip and one end of the eighteenth resistor R18. The other end of resistor R18 is connected to one end of the twentieth resistor R20 and the positive terminal of the detection signal. The other end of the twentieth resistor R20 is connected to the twenty-second resistor R22 and the negative terminal of the detection signal. The other end of the twenty-second resistor R22 is connected to COM. The above switching circuit includes the sixth analog switch chip D6, the thirty-first resistor R31, and the twenty-third capacitor C23. Pin 16 of the sixth analog switching chip D6 is connected to one end of the twenty-third capacitor C23. The other end of the twenty-third capacitor C23 is connected to COM. Pin 6 of the sixth analog switching chip D6 is connected to the thirty-first resistor R31 and COM. The other end of the thirty-first resistor R31 is connected to pin 15 of the sixth analog switching chip D6. Pin 2 of the sixth analog starter chip D6 is connected to the positive terminal of the detection signal. Pin 4 of the sixth analog starter chip D6 is connected to the positive terminal of the temperature sensor signal. Pin 9 of the sixth analog starter chip D6 is connected to the negative terminal of the detection signal. Pin 7 of the sixth analog starter chip D6 is connected to the negative terminal of the temperature sensor signal. Pin 1 of the sixth analog starter chip D6 is connected to switch control signal 1. Pin 10 of the sixth analog starter chip D6 is connected to switch control signal 2. Pin 11 of the sixth analog starter chip D6 is connected to switch control signal 3. Pin 20 of the sixth analog starter chip D6 is connected to switch control signal 4. Pin 3 of the sixth analog starter chip D6 is connected to S2_HIGH. Pin 8 of the sixth analog starter chip D6 is connected to S2_SENSE.

3. The circuit as described in claim 2, characterized in that, The fourth reference source chip D4 is specifically model REF5050AIDR, the fifth operational amplifier chip D5 is specifically model OPA197QDGKRQ1, and the sixth analog starter chip D6 is specifically model TMUX6234PWR.

4. The circuit as described in claim 1, characterized in that, The temperature measurement circuit includes a driving circuit and a signal acquisition circuit. The driving circuit includes a first reference source chip D1, a second operational amplifier chip D2, a third operational amplifier chip D3, a first resistor R1, a second resistor R3, a third resistor R3, a fourth resistor R4, a fifth resistor R5, a sixth resistor R6, a seventh resistor R7, an eighth resistor R8, a ninth resistor R9, a tenth resistor R10, an eleventh resistor R11, a twelfth resistor R12, a thirteenth resistor R13, a fourteenth resistor R14, a fifteenth resistor R15, a sixteenth resistor R16, a first capacitor C1, a second capacitor C2, a third capacitor C3, a fourth capacitor C4, a fifth capacitor C5, a sixth capacitor C6, a seventh capacitor C7, and an eighth capacitor C8. The first reference source chip D1... Pin 2 of the first op-amp chip is connected to one end of the first capacitor C1 and the second capacitor C2, and the +15V power supply. The other end of the first capacitor C1 and the second capacitor C2 is connected to COM. Pin 6 of the first reference source chip is connected to one end of the third capacitor C3 and the fourth capacitor C4, and the 5V reference source signal. The other end of the third capacitor C3 and the fourth capacitor C4 is connected to COM. Pin 2 of the second op-amp chip D2 is connected to one end of the first resistor R1 and the second resistor R2. The other end of the first resistor R1 is connected to COM. The other end of the second resistor R2 is connected to one end of the third resistor R3 and the fourth resistor R4, and pin 1 of the second op-amp chip D2. The other end of the third resistor R3 and the fourth resistor R4 is connected to one end of the seventh resistor R7 and the temperature sensor H. The IGH signal is connected. The other end of the seventh resistor R7 is connected to pin 5 of the second operational amplifier D2. Pin 3 of the second operational amplifier D2 is connected to one end of the fifth resistor R5 and the sixth resistor R6. The other end of the fifth resistor R5 is connected to the 5V reference signal. The other end of the sixth resistor R6 is connected to pins 7 and 6 of the second operational amplifier chip D2. Pin 11 of the second operational amplifier chip D2 is connected to one end of the fifth capacitor C5 and the -15V power supply. The other end of the fifth capacitor C5 is connected to COM. Pin 4 of the second operational amplifier chip D2 is connected to one end of the sixth capacitor C6 and the +15V power supply. The other end of the sixth capacitor C6 is connected to COM. Pin 9 of the second operational amplifier chip D2 is connected to the eighth resistor R8 and the ninth resistor R9. One end of the resistor R8 is connected to the COM terminal. The other end of the resistor R9 is connected to one end of the tenth and eleventh resistors R10 and R11, and to pin 8 of the second operational amplifier chip D2. The other ends of the resistors R10 and R11 are connected to one end of the fourteenth resistor R14 and the SENSE signal terminal of the temperature sensor. The other end of the fourteenth resistor R14 is connected to pin 12 of the second operational amplifier D2. Pin 10 of the second operational amplifier D2 is connected to one end of the twelfth and thirteenth resistors R12 and R13. The other end of the twelfth resistor R12 is connected to the 5V reference signal. The other end of the thirteenth resistor R13 is connected to pins 14 and 13 of the second operational amplifier chip D2.Pin 5 of the third operational amplifier chip D3 is connected to one end of the seventh capacitor C7, the eighth capacitor C8, the sixteenth resistor R16, and the LOW signal terminal of the temperature sensor. The other end of the seventh capacitor C7, the eighth capacitor C8, and the sixteenth resistor R16 is connected to COM. Pin 6 of the third operational amplifier chip D3 is connected to pin 7 of the third operational amplifier chip D3 and one end of the fifteenth resistor R15. The other end of the fifteenth resistor R15 is connected to the reference signal of the temperature sensor. The above signal acquisition circuit includes the seventh operational amplifier chip D7, the twenty-fifth resistor R25, the twenty-sixth resistor R26, and the thirtieth resistor R30. Pin 4 of op-amp chip D7 is connected to S2_HIGH; pin 1 of op-amp chip D7 is connected to S2_SENSE; pin 2 of op-amp chip D7 is connected to one end of resistor R25 (the 25th resistor); the other end of resistor R25 is connected to pin 3 of op-amp chip D7; pin 6 of op-amp chip D7 is connected to one end of resistor R30 (the 30th resistor); the other end of resistor R30 is connected to COM; pin 7 of op-amp chip D7 is connected to one end of resistor R26 (the 26th resistor); the other end of resistor R26 is connected to the S_TEMP signal. The first reference source chip D1 is specifically model REF5050AIDR, the second operational amplifier chip D2 is specifically model OPA4197QPWRQ1, the third operational amplifier chip D3 is specifically model OPA2197QDGKRQ1, and the seventh operational amplifier chip D7 is specifically model INA849DR.

5. The circuit as described in claim 1, characterized in that, The monitoring circuit includes a ninth comparator chip D9, a tenth reference source chip D10, a thirty-third resistor R33, a thirty-fourth resistor R34, a thirty-fifth resistor R35, a thirty-sixth resistor R36, a twenty-ninth capacitor C29, and a thirtieth capacitor C30. Pin 2 of the tenth reference source chip D10 is connected to the +15V power supply, one end of the twenty-ninth capacitor C29, and one end of the thirtieth capacitor C30. The other end of the twenty-ninth capacitor C29 and the thirtieth capacitor C30 is connected to COM. Pin 6 of the tenth reference source chip D10 is connected to one end of the thirty-sixth resistor R36. The other end of resistor R36 is connected to pin 2 of the ninth comparator chip. Pin 3 of the ninth comparator chip is connected to one end of the thirty-fifth resistor R35 and one end of the thirty-third resistor R33. The other end of the thirty-fifth resistor R35 is connected to the S_TEMP signal. The other end of the thirty-third resistor R33 is connected to pin 1 of the ninth comparator chip, one end of the thirty-fourth resistor R34, and the T2A95 signal. The other end of the thirty-fourth resistor R34 is connected to the 3.3V power supply. Pin 8 of the ninth comparator chip is connected to the 28V power supply. Pin 4 of the ninth comparator chip is connected to COM. The ninth comparator chip D9 is specifically model REF5010AIDR, and the tenth reference source chip D10 is specifically model LM2903BQDRQ1.

6. The circuit as described in claim 1, characterized in that, The latching circuit includes an eleventh NOR gate chip D11, a twelfth NOR gate chip D12, a thirteenth OR gate chip D13, a thirty-seventh resistor R37, a thirty-eighth resistor R38, a thirty-ninth resistor R39, and a fortieth resistor R40. Pin 1 of the eleventh NOR gate chip D11 is connected to one end of the thirty-eighth resistor R38 and the RESET_TEMP2 reset signal; the other end of the thirty-eighth resistor R38 is connected to DGND. Pin 5 of the eleventh NOR gate chip D11 is connected to a 3.3V power supply. Pin 3 of the eleventh NOR gate chip D11 is connected to DGND. Pin 2 of the eleventh NOR gate chip D11 is connected to pin 4 of the twelfth NOR gate chip D12. Pin 4 of the eleventh NOR gate chip D11 is connected to pin 2 of the twelfth NOR gate chip D12 and the fortieth resistor R40. One end is connected to pin 1 of the thirteenth OR gate chip D13; the other end of the thirty-seventh resistor R37 is connected to DGND; pin 1 of the twelfth NOR gate chip D12 is connected to one end of the fortieth resistor R40 and the T2A95 signal; the other end of the fortieth resistor R40 is connected to DGND; pin 3 of the twelfth NOR gate chip D12 is connected to DGND; pin 5 of the twelfth NOR gate chip D12 is connected to the 3.3V power supply; pin 5 of the thirteenth OR gate chip D3 is connected to the 3.3V power supply; pin 2 of the thirteenth OR gate chip D3 is connected to one end of the thirty-ninth resistor R39 and the T2A95 signal; the other end of the thirty-ninth resistor R39 is connected to DGND; pin 3 of the thirteenth OR gate chip D3 is connected to DGND; pin 4 of the thirteenth OR gate chip D3 is connected to the T2_AWARN signal. The eleventh NOR gate chip D11 is specifically model SN74LVC1G02DBVR, the twelfth NOR gate chip D12 is specifically model SN74LVC1G02DBVR, and the thirteenth OR gate chip D13 is specifically model SN74LVC1G32QDCKRQ1.

7. The circuit as described in claim 1, characterized in that, The cutoff circuit includes a fifteenth inverter D15, a sixteenth switch chip D16, a first diode VD1, a forty-first resistor R41, a forty-second resistor R42, a forty-third resistor R43, a forty-fifth resistor R45, a forty-sixth resistor R46, a forty-sixth capacitor C46, ​​and a forty-seventh capacitor C47. Pin 5 of the fifteenth inverter D15 is connected to a 3.3V power supply; pin 3 of the fifteenth inverter D15 is connected to DGND; pin 2 of the fifteenth inverter D15 is connected to one end of the forty-first resistor R41 and the T2_AWARN signal; the other end of the forty-first resistor R41 is connected to DGND; pin 4 of the fifteenth inverter D15 is connected to one end of the forty-fifth resistor R45; the other end of the forty-fifth resistor R45 is connected to pin 1 of the sixteenth switch chip D16; pin 8 of the sixteenth switch chip D16 is connected to a 28V power supply and one end of the forty-third resistor R43; the other end of the forty-third resistor R43 is connected to the... Pin 2 of the sixteenth switch chip D16 is connected. Pin 4 of the sixteenth switch chip D16 is connected to one end of the forty-sixth resistor R46. The other end of the forty-sixth resistor R46 is connected to COM. Pin 7 of the sixteenth switch chip D16 is connected to one end of the first diode VD1. The other end of the first diode VD1 is connected to one end of the forty-second resistor R42 and the 28V_FB signal. The other end of the forty-second resistor R42 is connected to one end of the forty-sixth capacitor C46 and the 28V_PWR signal. The other end of the forty-sixth capacitor C46 is connected to COM. Pin 5 of the sixteenth switch chip D16 is connected to one end of the forty-seventh capacitor C47. The other end of the forty-seventh capacitor C47 is connected to pins 6 and 9 of the sixteenth switch chip D16 and COM. The specific model of the fifteenth inverter D15 is SN74LVC1G14QDCKRQ1, and the specific model of the sixteenth switch chip D16 is TPS1H200AQDGNRQ1.

8. The airborne valve over-temperature protection method for the circuit described in any one of claims 1-7, characterized in that, The self-test circuit is connected to the temperature measurement circuit and is responsible for sending a simulated self-test signal upon power-on and switching the signal source to a simulated self-test signal to perform hardware circuit self-tests. This includes power-on self-tests of the temperature measurement circuit, monitoring circuit, latching circuit, and cut-off circuit. The temperature measurement circuit includes a drive circuit and a signal acquisition circuit, responsible for outputting the temperature sensor excitation signal and acquiring the temperature sensor feedback signal. The monitoring circuit includes a comparison circuit and a reference source circuit, responsible for issuing an over-temperature alarm signal when the temperature exceeds a set threshold. The latching circuit stores the alarm signal from the monitoring circuit; the over-temperature signal can only be cleared upon receiving a reset signal. The cut-off circuit is connected to the airborne valve power supply; when it receives a cut-off signal from the signal latching circuit, the power cut-off circuit cuts off the 28V power supply to the valve, closing it.

9. The method as described in claim 8, characterized in that, Includes the following steps: Step 1: A method and circuit for over-temperature protection of airborne valves with self-testing function, characterized in that the self-testing circuit is used to test the accuracy of the over-temperature protection circuit of the airborne valve. During power-on self-test, the signal source is switched to the self-testing circuit, which generates an analog self-testing signal and transmits it to the back-end temperature measurement circuit, isolation monitoring circuit, and cut-off circuit. The valve switch status signal is also sampled back to detect whether the 28V power supply to the airborne valve is cut off. Step 2: A method and circuit for airborne valve over-temperature protection with self-testing function, characterized in that the system only operates normally after the self-testing circuit verifies that the airborne valve over-temperature protection circuit is functioning normally; if the power-on self-test of the self-testing circuit fails, the system reports a fault. Step 3: An airborne valve over-temperature protection method and circuit with self-detection function, characterized in that the temperature measuring circuit includes a driving circuit and a signal acquisition circuit. The driving circuit is composed of a constant current source circuit, which is responsible for providing current excitation to the temperature sensor. The signal acquisition circuit is composed of a filter circuit and a precision instrument amplification circuit, which is responsible for acquiring and processing the temperature sensor signal. Step 4: An airborne valve over-temperature protection method and circuit with self-detection function, characterized in that the monitoring circuit includes a comparison circuit and a reference source circuit. The reference source circuit outputs the reference value of the comparison circuit as A, the temperature alarm value as B, and the gain of the precision instrument amplification circuit in the temperature measurement circuit is G, where A=B*G. By configuring the value of G, alarms for different temperatures can be matched. Step 5: An airborne valve over-temperature protection method and circuit with self-detection function, characterized in that the latching circuit is responsible for storing the over-temperature alarm signal issued by the monitoring circuit. The latching circuit will only clear the alarm signal after receiving a reset signal from the software BIT, ensuring that the cut-off signal issued by the latching circuit will not automatically recover due to the disappearance of the fault. Step 6: An airborne valve over-temperature protection method and circuit with self-detection function, characterized in that the power cut-off circuit controls the 28V power supply of the airborne valve. When the airborne system is running normally, 28V is connected and the airborne valve is open. When a fault signal occurs, the power cut-off circuit will cut off the 28V power supply of the airborne valve and close the valve to ensure the safety of the airborne system. Step 7: A method and circuit for over-temperature protection of an airborne valve with self-detection function, characterized in that the cut-off circuit controls the power supply of the airborne valve through a high-side switch. When a cut-off signal is received, the high-side switch cuts off the power supply to the valve, and the valve closes to ensure system safety.

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